Pakistan became an Islamic republic in 1956.

King's special, "Unthinkable: The Alzheimer's Epidemic," airs Sunday at 8 p.m. EDT/PDT on CNN.

Apollo 11 and its astronauts, Neil Armstrong, Edwin "Buzz" Aldrin and Michael Collins, went into orbit around the moon in 1969.

West Virginia became the 35th state in 1863.